MOA-2007-BLG-192Lb, occasionally shortened to MOA-192 b,Planet Quest: New Worlds Atlas
, JPL. Accessed on line July 2, 2008. is an

extrasolar planet An exoplanet or extrasolar planet is a planet outside the Solar System. The first possible evidence of an exoplanet was noted in 1917 but was not recognized as such. The first confirmation of detection occurred in 1992. A different planet, init ...

approximately 3,000 light-years away in the constellation of Sagittarius. The planet was discovered orbiting the

brown dwarf Brown dwarfs (also called failed stars) are substellar objects that are not massive enough to sustain nuclear fusion of ordinary hydrogen ( 1H) into helium in their cores, unlike a main-sequence star. Instead, they have a mass between the most ...

or low-mass star

MOA-2007-BLG-192L MOA-2007-BLG-192L is a low-mass red dwarf star or brown dwarf, approximately 3,000 light-years away in the constellation of Sagittarius. It is estimated to have a mass approximately 6% of the Sun's. In 2008, an Earth-sized extrasolar plane ...

. At a mass of approximately 3.3 times Earth, it is one of the lowest-mass extrasolar

planet A planet is a large, rounded astronomical body that is neither a star nor its remnant. The best available theory of planet formation is the nebular hypothesis, which posits that an interstellar cloud collapses out of a nebula to create a you ...

s at the time of discovery. It was found when it caused a gravitational

microlensing Gravitational microlensing is an astronomical phenomenon due to the gravitational lens effect. It can be used to detect objects that range from the mass of a planet to the mass of a star, regardless of the light they emit. Typically, astronomers ...

event on May 24, 2007, which was detected as part of the MOA-II microlensing survey at the Mount John University Observatory in

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

. The system's primary is small as well. At roughly 6% the mass of the

Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

, it is probably too small to sustain

fusion Fusion, or synthesis, is the process of combining two or more distinct entities into a new whole. Fusion may also refer to: Science and technology Physics *Nuclear fusion, multiple atomic nuclei combining to form one or more different atomic nucl ...

reactions, making it a dimly glowing brown dwarf. Also, the estimated projected distance between MOA-2007-BLG-192Lb and its primary is approximately 0.62

astronomical unit The astronomical unit (symbol: au, or or AU) is a unit of length, roughly the distance from Earth to the Sun and approximately equal to or 8.3 light-minutes. The actual distance from Earth to the Sun varies by about 3% as Earth orbits ...

s. That means the planet probably formed with much ice and gases, more like Neptune (an

ice giant An ice giant is a giant planet composed mainly of elements heavier than hydrogen and helium, such as oxygen, carbon, nitrogen, and sulfur. There are two ice giants in the Solar System: Uranus and Neptune. In astrophysics and planetary scienc ...

planet) in composition than

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...

terrestrial planet A terrestrial planet, telluric planet, or rocky planet, is a planet that is composed primarily of silicate rocks or metals. Within the Solar System, the terrestrial planets accepted by the IAU are the inner planets closest to the Sun: Mercury, ...

), according to astronomer David Bennett of the

University of Notre Dame The University of Notre Dame du Lac, known simply as Notre Dame ( ) or ND, is a private Catholic university, Catholic research university in Notre Dame, Indiana, outside the city of South Bend, Indiana, South Bend. French priest Edward Sorin fo ...

.Smallest Extrasolar Planet Portends Other Earths
Richard A. Kerr, ''ScienceNOW Daily News'', June 2, 2008. Accessed on line June 16, 2008.

References

External links

* {{DEFAULTSORT:MOA-2007-BLG-192Lb Sagittarius (constellation) Super-Earths Terrestrial planets Exoplanets discovered in 2008 Exoplanets detected by microlensing